Since 2000, NIOSH has conducted a number of epidemiologic studies on respiratory and non-respiratory health in occupants of damp/moldy buildings, and collected more than 2,000 floor/chair dust samples which have been being stored in -80C freezers. The existing database from those studies includes measurements on culturable fungi and bacteria, fungal cell wall components (ergosterol and glucan), and bacterial cell wall components (endotoxin and peptidoglycan) as well as occupants? health. Significant associations between various adverse respiratory and non-respiratory health effects and exposure to fungal biomarkers have been demonstrated. This project continues that work and further examine associations of exposure to mycotoxins with occupants? health by building the capability of analyzing indoor environmental samples for multiple mycotoxins in a single sample analysis. The new method will utilize a sample extraction and LC protocol that is suitable for determining multiple mycotoxins in indoor environmental samples using UPLC-MSMS by modifying the HPLC-MSMS methods recently developed for analysis of food and feed samples. Once the protocol is fully developed, NIOSH will apply the method to analyze archived dust samples collected from previous epidemiologic studies of occupants of water-damaged buildings and new samples collected from a NIOSH-funded environmental survey on schools in FY2015. The knowledge gained from these studies will also address specific NIOSH and NIEHS research goals for reducing environmental and occupational causes or contributing factors to acute and chronic illnesses and diseases in worker populations as well as children.